Method and apparatus for selectively enabling reception of downlink signaling channels

ABSTRACT

In a wireless communication system including a wireless transmit/receive unit (WTRU) and at least one Node-B, a method and apparatus is used to selectively enable reception of at least one downlink (DL) enhanced uplink (EU) signaling channel established between the WTRU and the Node-B(s). During the operation of an enhanced dedicated channel (E-DCH), the WTRU monitors at least one DL EU signaling channel established between the WTRU and the Node-B(s) only when it is necessary, based on the WTRU&#39;s knowledge of at least one established standard procedure. The WTRU coordinates and consolidates DL signaling channel reception requirements of a plurality of channel allocation and/or data transmission procedures carried out by the WTRU in accordance with the established standard procedure. The WTRU determines whether to enable reception of at least one specific DL signaling channel based on the consolidated DL signaling channel reception requirements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/095,401, filed Mar. 31, 2005, which claims the benefit of U.S.Provisional Application No. 60/566,620 filed Apr. 29, 2004, which areincorporated by reference as if fully set forth.

FIELD OF INVENTION

The present invention is related to a wireless communication systemincluding a wireless transmit/receive unit (WTRU) and at least oneNode-B. More particularly, the present invention is a method andapparatus for selectively enabling reception of downlink (DL) enhanceduplink (EU) signaling channels established between the WTRU and theNode-B(s).

BACKGROUND

Methods for improving uplink (UL) coverage, throughput and transmissionlatency are being investigated in Release 6 (R6) of the 3rd GenerationPartnership Project (3GPP). In order to successfully implement thesemethods, the scheduling and assigning of UL radio resources have beenmoved from a radio network controller (RNC) to a Node-B such that theNode-B can make decisions and manage UL radio resources on a short-termbasis more efficiently than the RNC, even if the RNC retains overallcontrol over the Node-B.

EU operation requires transmitting information such as UL channelallocations and transmission feedback information to the WTRU via DL EUsignaling channels. The WTRU monitors the DL EU signaling channels forthe reception of channel allocations and transmission feedbackinformation.

A method and apparatus is desired for controlling reception of the DL EUsignaling channels such that they are enabled only when required.

SUMMARY

The present invention is a method and apparatus for selectively enablingreception of at least one DL EU signaling channel used for EU operation.During the operation of an enhanced dedicated channel (E-DCH), a WTRUmonitors at least one DL EU signaling channel established between theWTRU and at least one Node-B only when it is necessary, based on theWTRU's knowledge of at least one established standard procedure. TheWTRU coordinates and consolidates DL signaling channel receptionrequirements of a plurality of channel allocation and/or datatransmission procedures carried out by the WTRU in accordance with theestablished standard procedure. The WTRU determines whether to enablereception of at least one specific DL signaling channel based on theconsolidated DL signaling channel reception requirements.

In accordance with the present invention, the WTRU does not have tocontinuously enable the reception of the DL EU signaling channel duringEU operation. Instead, the WTRU may selectively turn on and off, (i.e.,enable and disable), reception of at least one specific DL EU signalingchannel, thus reducing WTRU processing requirements and reducing theprobability of misinterpretation of DL signaling.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from thefollowing description of a preferred example, given by way of exampleand to be understood in conjunction with the accompanying drawingwherein:

FIG. 1 is a block diagram of a wireless communication system operatingin accordance with the present invention;

FIG. 2 is a flow diagram of a process including method steps forselectively enabling reception of at least one DL EU signaling channelduring EU operation when the WTRU sends an EU channel allocation requestand is expecting to receive scheduling information in accordance withone embodiment of the present invention; and

FIG. 3 is a flow diagram of a process including method steps forselectively enabling reception of at least one DL EU signaling channelwhen the WTRU sends E-DCH data and is expecting to receive feedbackinformation in accordance with another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Hereafter, the terminology “WTRU” includes but is not limited to a userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, or any other type of device capable of operating in a wirelessenvironment. When referred to hereafter, the terminology “Node-B”includes but is not limited to a base station, a site controller, anaccess point or any other type of interfacing device in a wirelessenvironment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 is a block diagram of a wireless communication system 100operating in accordance with the present invention. The system 100includes a WTRU 102, at least one Node-B 104 and an RNC 106. The WTRU102 includes an E-DCH data buffer 112, a physical reception controlentity 114, a receiver 116, a transmitter 118, a processor 120 and astandards database 122.

The transmitter 118 in the WTRU 102 transmits an EU channel allocationrequest, (i.e., a rate request), to the Node-B(s) 104 through a UL EUchannel 108 for EU transmission to the Node-B 104. The EU channelallocation request may include scheduling information. The schedulinginformation may include traffic volume measurement (TVM) information ofE-DCH data stored in the buffer 112 of the WTRU 102 and available EUtransmit power information.

After the EU channel allocation request is transmitted, the receiver 116in the WTRU 102 monitors a plurality of DL EU signaling channels 1101,1102, . . . , 110N for channel allocation information via the physicalreception control entity 114. The Node-B(s) 104 responds to the EUchannel allocation request with UL channel allocation informationthrough one of the DL EU signaling channels 110 _(1-N).

The system 100 is configured such that both UL signaling and E-DCH dataare transmitted from the WTRU 102 to the Node-B(s) 104 via the UL EUchannel 108. After receiving scheduling information for channelallocation from the Node-B(s) 104 through at least one of the DL EUsignaling channels 110 _(1-N), the transmitter 118 in the WTRU 102transmits E-DCH data through the allocated UL EU channel 108. Thereceiver 116 in the WTRU 102 then monitors the DL EU signalingchannel(s) 110 _(1-N) for expected E-DCH data feedback information.

In response to receiving the E-DCH data, the Node-B(s) 104 transmitsE-DCH data feedback information to the WTRU 102 through the DL EUsignaling channels 110 _(1-N). The feedback information includes eithera positive acknowledgement (ACK) message or a negative acknowledgement(NACK) message, depending on the success or failure of the Node-B(s) 104decoding the E-DCH data sent over the UL EU channel 108 by the WTRU 102.The Node-B(s) 104 may also transmit further channel allocationinformation in response to the E-DCH data transmission. Such furtherinformation may be included in the feedback information or may be sentas a separate transmission over the DL EU signaling channels 110 _(1-N).

The status of active EU procedures in the WTRU 102 may be used toprovide input to the physical reception control entity 114 of the WTRU102. The physical reception control entity 114 communicates with aphysical layer process to selectively enable and disable reception ofthe DL EU signaling channels 110 _(1-N).

In accordance with the present invention, the physical reception controlentity 114 in the WTRU 102 disables reception, (i.e., ceasesmonitoring), of the DL EU signaling channels 1101-N when it is notrequired by EU signaling procedures known to the WTRU 102. Duringperiods when the WTRU 102 is not required to receive the DL EU signalingchannels 110 _(1-N), the processing requirements and power consumptionof the WTRU 102 are reduced, and the possibility of false interpretationof DL signaling is avoided.

FIG. 2 is a flow diagram of a process 200 including method steps forselectively enabling reception of at least one DL EU signaling channel110 _(1-N) during EU transmission in accordance with the presentinvention. In step 202, the WTRU 102 is configured by the RNC 106 forE-DCH operation, whereby the UL EU channel 108 and the DL EU signalingchannel(s) 110 _(1-N) are established between the WTRU 102 and theNode-B(s) 104. The WTRU 102 is not required to enable the reception ofits DL EU signaling channel(s) 110 _(1-N) immediately followingconfiguration in the WTRU 102. Thus, the physical reception controlentity 114 in the WTRU 102 disables reception of DL EU signal channel(s)110 _(1-N).

Still referring to FIG. 2, after the WTRU 102 is configured for E-DCHoperation at step 202, the WTRU 102 monitors its buffer 112 of E-DCHdata (step 204). If, at step 206, it is determined by the WTRU 102 thatthere is no E-DCH data in the buffer 112, the WTRU 102 continues tomonitor the buffer 112, and reception of the DL EU signaling channels110 _(1-N) remains disabled at step 204. If, at step 206, it isdetermined by the WTRU 102 that there is E-DCH data waiting (i.e.,queued) for transmission via the UL EU channel 108, the WTRU 102transmits an EU channel allocation request with or without E-DCH data tothe Node-B(s) 104 via the UL EU channel 108 and enables reception of atleast one DL EU signaling channel 110 _(1-N) (step 208). The WTRU 102may optionally enable reception of DL EU signaling channel(s) 110 _(1-N)after a predetermined or calculated delay. The EU channel allocationrequest may include scheduling information such as TVM information andavailable EU transmit power information.

Operation of E-DCH requires radio resource allocations to be scheduledand signaled by the Node-B(s) 104 to the WTRU 102 in response to an EUchannel allocation request transmitted by the WTRU 102. According toestablished signaling procedures, the WTRU 102 keeps track of when E-DCHdata transmission scheduling information including EU channelallocations is required or expected to be received from the Node-B(s) onat least one DL EU signaling channel 110 _(1-N) based on informationindicating when the EU channel allocation request was transmitted by theWTRU 102 (step 210).

In step 212, the WTRU 102 receives the required or expected schedulinginformation from the Node-B(s) over the DL EU signaling channel(s) 110_(1-N) and then, if not required by any one entity, the physicalreception control entity 114 disables reception of DL EU signalingchannel(s) 110 _(1-N). Optionally, in step 214, the WTRU 102 schedulesreception of DL EU signaling channel(s) 110 _(1-N) based on periodicallyreceived DL EU signaling channel scheduling information if configured.Reception of specific DL EU signaling channel(s) 110 _(1-N) is enabled,depending on which EU signaling procedures are active in the WTRU 102.

FIG. 3 is a flow diagram of a process 300 including method steps forselectively enabling reception of the DL EU signaling channels 110_(1-N) when the WTRU 102 sends E-DCH data and is expecting to receivefeedback information in accordance with another embodiment of thepresent invention. In step 302, the WTRU 102 is configured by the RNC106 for E-DCH operation whereby the UL EU channel 108 and the DL EUsignaling channel(s) 110 _(1-N) are established between the WTRU 102 andthe Node-B(s) 104. The WTRU 102 is not required to enable the receptionof its DL EU signaling channel(s) 110 _(1-N) immediately following theE-DCH operation configuration of the WTRU 102. Thus, the physicalreception control entity 114 in the WTRU 102 disables reception of DL EUsignal channel(s) 110 _(1-N).

Still referring to FIG. 3, after the WTRU 102 is configured to performan E-DCH operation at step 302, the WTRU 102 monitors its buffer 112 ofE-DCH data (step 304). If at step 306 it is determined by the WTRU 102that there is no E-DCH data in the buffer 112, the WTRU 102 continues tomonitor the buffer 112, and reception of the DL EU signaling channel(s)110 _(1-N) remains disabled at step 304.

Steps 308, 310, 312 and 314 of process 300 may be performed for each ofa plurality of several hybrid-automatic repeat request (H-ARQ) processesoperating in parallel in the WTRU. If at step 306 it is determined bythe WTRU 102 that there is E-DCH data waiting (i.e., queued) fortransmission via the UL EU channel 108, for each H-ARQ process, the WTRU102 transmits E-DCH data with or without an EU channel allocationrequest to the Node-B(s) 104 via the UL EU channel 108 and enablesreception of DL EU signaling channel(s) 110 _(1-N) (step 308). The WTRU102 may optionally enable reception of DL EU signaling channel(s) 110_(1-N) after a predetermined or calculated delay.

According to established signaling procedures, the WTRU 102 keeps trackof when feedback information is required or expected to be received fromthe Node-B(s) 104 for each H-ARQ process (step 310). In step 312, theWTRU receives feedback information from the Node-B(s) 104 and disablesreception of the DL EU signaling channel(s) 110 _(1-N) if not requiredby any one entity. Optionally, in step 314, the WTRU 102 schedulesreception of the DL EU signaling channel(s) 110 _(1-N) based onperiodically received feedback information if configured. Reception ofspecific DL EU signaling channel(s) 110 _(1-N) is enabled, depending onwhich EU signaling procedures are active in the WTRU 102.

The WTRU 102 keeps track of when scheduling information including EUchannel allocations is expected to be received on DL EU signalingchannels 110 _(1-N) based on information indicating when the WTRU 102transmitted the E-DCH data. DL EU signaling channels 110 _(1-N) are alsoused to provide the WTRU 102 feedback information from the Node-B(s) 104for E-DCH transmissions. Since feedback transmitted to the WTRU is inresponse to a specific action of the WTRU, the time of feedbackinformation reception at the WTRU can be accurately determined by theWTRU. Feedback information transmitted by the Node-B(s) 104 via the DLEU signaling channel(s) 110 _(1-N) may consist of H-ARQ acknowledgementsand/or UL channel allocation information. One example of WTRU receptionof feedback channels could be H-ARQ information channels (HICHs) andrelative grant channels (RGCHs) or absolute grant channels (AGCH) in3GPP.

The H-ARQ operation may be either synchronous or asynchronous. Insynchronous operation, the WTRU 102 knows exactly when the WTRU 102 mayreceive the feedback (ACK or NACK) via DL EU signaling channel(s) 110_(1-N) and the WTRU 102 enables reception of the DL EU signalingchannel(s) 110 _(1-N) in accordance with a preconfigured schedule. Withasynchronous H-ARQ operation, the WTRU enables reception of the DL EUsignaling channel(s) 110 _(1-N) for a predetermined time periodfollowing the EU transmission for receiving the feedback.

Channel allocation feedback may also be transmitted to the WTRU 102 fromthe Node-B(s) 104 on DL EU signaling channel(s) 110 _(1-N). The WTRU 102may also enable reception of DL EU signaling channel(s) 110 _(1-N) forthis channel allocation feedback information. EU channel allocationprocedures known to the WTRU 102 allow the WTRU 102 to schedulereception of this information. The channel allocation feedback mayeither be synchronized with the H-ARQ feedback, send over apredetermined period, or have a specified periodic repetition that theWTRU 102 can schedule reception for.

If the WTRU 102 does not send a channel allocation request to theNode-B(s) 104, but all previous EU data transmission requests sent bythe WTRU 102 have been serviced by the Node-B(s) 104, and feedbackinformation was received from the Node-B for all outstanding H-ARQtransmissions, then the WTRU 102 disables the reception of the DL EUsignaling channel(s) 110 _(1-N).

In one embodiment, the WTRU 102 sends at least one channel allocationrequest to a plurality of Node-Bs 104 via at least one UL channel 108,and the Node-Bs send channel allocation information to the WTRU 102 viarespective downlink (DL) signaling channels 110 _(1-N) in response toreceiving the channel allocation request.

The processor 120 in the WTRU 102 coordinates and consolidates DLsignaling channel reception requirements of a plurality of channelallocation procedures carried out by the WTRU 102 in accordance with atleast one established standard procedure stored in the standardsdatabase 122, and determines whether or not to enable reception ofspecific ones of the DL signaling channels 110 _(1-N) based on theconsolidated DL signaling channel reception requirements. The standardsdatabase 120 is in communication with the processor 120 and provides theprocessor 120 with information associated with at least one establishedstandard procedure. The transmitter 118 is in communication with theprocessor 120 and sends at least one channel allocation request to theNode-Bs 104 via at least one UL channel 108. The receiver 116 is incommunication with the processor 120 and receives channel allocationinformation from the Node-Bs 104 over the DL signaling channels 110_(1-N). The physical reception control entity 114 is in communicationwith the processor 120 and the receiver 116. The physical receptioncontrol entity 114 enables or disables reception of specific ones of theDL signaling channels 110 _(1-N) based on the determination made by theprocessor 120.

In another embodiment, the WTRU 102 sends at least one data transmissionto a plurality of Node-Bs 104 via at least one UL channel 108, and theNode-Bs 104 send data transmission feedback information to the WTRU 102via respective downlink (DL) signaling channels 110 _(1-N) in responseto receiving the data transmission.

The processor 120 in the WTRU 102 coordinates and consolidates DLsignaling channel reception requirements of a plurality of datatransmission procedures carried out by the WTRU in accordance with atleast one established standard procedure stored in the standardsdatabase 122, and determines whether or not to enable reception ofspecific ones of the DL signaling channels 110 _(1-N) based on theconsolidated DL signaling channel reception requirements. The E-DCH databuffer 112 is in communication with the processor 120 and queues data tobe included in at least one data transmission sent by the WTRU 102 tothe Node-Bs 104 via at least one UL channel 108. The transmitter 118 isin communication with the processor and sends the at least one datatransmission to the Node-Bs 104. The receiver 116 is in communicationwith the processor 120 and receives data transmission feedbackinformation from the Node-Bs 104 over the DL signaling channels 110_(1-N). The physical reception control entity 114 is in communicationwith the processor 120 and the receiver 116. The physical receptioncontrol entity 114 enables or disables reception of specific ones of theDL signaling channels 110 _(1-N) based on the determination made by theprocessor 120.

In yet another embodiment, the WTRU 102 sends at least one channelallocation request and E-DCH data to a plurality of Node-Bs 104 via atleast one UL channel 108, and the Node-Bs send channel allocationinformation and data feedback information associated with the E-DCH datato the WTRU 102 via respective downlink (DL) signaling channels 110_(1-N) in response to receiving the at least one channel allocationrequest and E-DCH data.

The processor 120 in the WTRU 102 coordinates and consolidates DLsignaling channel reception requirements of a plurality of channelallocation procedures and data transmission procedures carried out bythe WTRU 102 in accordance with at least one established standardprocedure stored in the standards database 122, and determines whetheror not to enable reception of specific ones of the DL signaling channels110 _(1-N) based on the consolidated DL signaling channel receptionrequirements. The standards database 120 is in communication with theprocessor 120 and provides the processor 120 with information associatedwith at least one established standard procedure. The transmitter 118 isin communication with the processor 120 and sends at least one channelallocation request and E-DCH data to the Node-Bs 104 via at least one ULchannel 108. The receiver 116 is in communication with the processor 120and receives channel allocation information from the Node-Bs 104 overthe DL signaling channels 110 _(1-N). The physical reception controlentity 114 is in communication with the processor 120 and the receiver116. The physical reception control entity 114 enables or disablesreception of specific ones of the DL signaling channels 110 _(1-N) basedon the determination made by the processor 120.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

What is claimed is:
 1. A wireless transmit/receive unit (WTRU)comprising: a transmitter configured to transmit enhanced uplink data; areceiver configured to receive an acknowledgment (ACK) or a negativeacknowledgment (NACK) on a hybrid automatic repeat request (H-ARQ)information channel (HICH) during a predetermined period after thetransmission of the enhanced uplink data; the receiver is furtherconfigured to receive configuration information; and a processorconfigured to enable the receiver to periodically receive at least anenhanced uplink absolute grant channel (E-AGCH) and an enhanced uplinkrelative grant channel (E-RGCH); the processor configured to control thereceiver to discontinue reception of the E-AGCH and the E-RGCH based onconfiguration information and between the periods that the receiver isenabled to receive the E-AGCH and the E-RGCH.
 2. The WTRU of claim 1wherein the processor is further configured to control the transmitterto transmit scheduling information including an amount of enhanceddedicated channel (E-DCH) data stored in a buffer.
 3. The WTRU of claim1 wherein the processor is further configured to control the transmitterto transmit scheduling information including available enhanced uplinktransmission power information.
 4. A method for channel resourceallocation comprising: transmitting enhanced uplink data; receiving anacknowledgment (ACK) or a negative acknowledgment (NACK) on a hybridautomatic repeat request (H-ARQ) information channel (HICH) during apredetermined period after the transmission of the enhanced uplink data;receiving configuration information; receiving at least an enhanceduplink absolute grant channel (E-AGCH) and an enhanced uplink relativegrant channel (E-RGCH) periodically; and discontinuing reception of theE-AGCH and the E-RGCH based on configuration information and between theperiods that at least the E-AGCH and the E-RGCH are received.
 5. Themethod of claim 4 further comprising transmitting scheduling informationincluding an amount of enhanced dedicated channel (E-DCH) data stored ina buffer.
 6. The method of claim 4 further comprising transmittingscheduling information including available enhanced uplink transmissionpower information.